1. Field of the Invention
The present invention relates to a roller holder, and more particularly to a roller holder having rollers arranged in different directions for engaging between two moving members and for preventing the impact onto the roller holder and for facilitating the sliding movement between the two moving members.
2. Description of the Prior Art
Typical screw shafts comprise a screw member threaded into a nut member, or relatively, a nut member engaged or threaded onto a screw member, and a number of balls engaged in the threads of the nut member and the screw member for facilitating the rotational and/or sliding movement between the nut member and the screw member.
Typical linear motion guide devices or other motion guide devices also comprise two moving members, such as a track rail and a slider slidably engaged with each other, and a number of balls or rollers or rolling members engaged between the two moving members for facilitating the sliding movement between the two moving members.
For example, U.S. Pat. No. 5,988,883 to Takamatu et al. disclose one of the typical endless retainer of guide devices for screw shafts or linear motion guide devices comprising an endless retainer for supporting and retaining a number of balls or rolling bodies together at predetermined intervals for rolling at an inside of two moving members or for being engaged between two moving members and for facilitating the sliding movement between the two moving members. The endless retainer includes a resin connector, and a number of interposing portions connected between two connecting portions for engaging with the ball bearing members or rolling bodies.
However, the interposing portions are connected and disposed between the ball bearing members or rolling bodies, and the ball bearing members or rolling bodies will impact onto and will scrape or scrub the interposing portions particularly when the endless retainer moves in a fast speed between the two moving members such that the abrasion or scraping between the interposing portions and the ball bearing members or rolling bodies will be greatly increased and such that the interposing portions will be quickly worn out.
U.S. Pat. No. 6,070,479 to Shirai discloses another typical rolling element string for a linear motion guide device comprising a link belt including multiple links connected in a line and each formed substantially like a ring with holding parts and having a receiving hole for a rolling element.
However, similarly, the holding parts are also connected and disposed between the rolling elements which will impact onto the holding parts when the rolling element string moves in a fast speed between the two moving members such that the abrasion or scraping between the holding parts and the rolling elements will be greatly increased and such that the holding parts will be quickly worn out or damaged.
U.S. Pat. No. 6,364,086 to Blaurock et al. discloses a further typical chain of rolling elements chain arrangement comprising a number of retainers coupled together with at least one elongate flexible element for coupling or retaining the rolling elements together.
However, similarly, the retainers are also connected and disposed between the rolling elements which will impact onto the retainers when the rolling element chain arrangement moves in a fast speed between the two moving members such that the abrasion or scraping between the retainers and the rolling elements will be greatly increased and such that the retainers will be quickly worn out or damaged.
U.S. Pat. No. 6,575,630 to Blaurock et al., and U.S. Pat. No. 6,830,378 to Michioka et al. disclose two still further typical rolling element chains or strings each also comprising a number of retainers coupled together with at least one elongate flexible element for coupling or securing or retaining the rolling elements together.
However, similarly, the retainers are also connected and disposed between the rolling elements which will impact onto the retainers when the rolling element chain arrangement moves in a fast speed between the two moving members such that the abrasion or scraping between the retainers and the rolling elements will be greatly increased and such that the retainers will be quickly worn out or damaged.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional roller holders for the screw shafts or for the linear motion guide devices.